/*
 * Written by Doug Lea with assistance from members of JCP JSR-166 Expert Group and released to the
 * public domain, as explained at http://creativecommons.org/publicdomain/zero/1.0/ Other
 * contributors include Andrew Wright, Jeffrey Hayes, Pat Fisher, Mike Judd.
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/test/tck/JSR166TestCase.java?revision=1.
 * 90 (We have made some trivial local modifications (commented out uncompilable code).)
 */

package com.google.common.util.concurrent;

import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.CodeSource;
import java.security.Permission;
import java.security.PermissionCollection;
import java.security.Permissions;
import java.security.Policy;
import java.security.ProtectionDomain;
import java.security.SecurityPermission;
import java.util.Arrays;
import java.util.Date;
import java.util.NoSuchElementException;
import java.util.PropertyPermission;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.Semaphore;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicReference;
import junit.framework.AssertionFailedError;
import junit.framework.TestCase;

/**
 * Base class for JSR166 Junit TCK tests. Defines some constants, utility methods and classes, as
 * well as a simple framework for helping to make sure that assertions failing in generated threads
 * cause the associated test that generated them to itself fail (which JUnit does not otherwise
 * arrange). The rules for creating such tests are:
 *
 * <ol>
 *
 * <li>All assertions in code running in generated threads must use the forms {@link #threadFail},
 * {@link #threadAssertTrue}, {@link #threadAssertEquals}, or {@link #threadAssertNull}, (not
 * {@code fail}, {@code assertTrue}, etc.) It is OK (but not particularly recommended) for other
 * code to use these forms too. Only the most typically used JUnit assertion methods are defined
 * this way, but enough to live with.</li>
 *
 * <li>If you override {@link #setUp} or {@link #tearDown}, make sure to invoke {@code super.setUp}
 * and {@code super.tearDown} within them. These methods are used to clear and check for thread
 * assertion failures.</li>
 *
 * <li>All delays and timeouts must use one of the constants {@code
 * SHORT_DELAY_MS}, {@code SMALL_DELAY_MS}, {@code MEDIUM_DELAY_MS}, {@code LONG_DELAY_MS}. The idea
 * here is that a SHORT is always discriminable from zero time, and always allows enough time for
 * the small amounts of computation (creating a thread, calling a few methods, etc) needed to reach
 * a timeout point. Similarly, a SMALL is always discriminable as larger than SHORT and smaller than
 * MEDIUM. And so on. These constants are set to conservative values, but even so, if there is ever
 * any doubt, they can all be increased in one spot to rerun tests on slower platforms.</li>
 *
 * <li>All threads generated must be joined inside each test case method (or {@code fail} to do so)
 * before returning from the method. The {@code joinPool} method can be used to do this when using
 * Executors.</li>
 *
 * </ol>
 *
 * <p>
 * <b>Other notes</b>
 * <ul>
 *
 * <li>Usually, there is one testcase method per JSR166 method covering "normal" operation, and then
 * as many exception-testing methods as there are exceptions the method can throw. Sometimes there
 * are multiple tests per JSR166 method when the different "normal" behaviors differ significantly.
 * And sometimes testcases cover multiple methods when they cannot be tested in isolation.</li>
 *
 * <li>The documentation style for testcases is to provide as javadoc a simple sentence or two
 * describing the property that the testcase method purports to test. The javadocs do not say
 * anything about how the property is tested. To find out, read the code.</li>
 *
 * <li>These tests are "conformance tests", and do not attempt to test throughput, latency,
 * scalability or other performance factors (see the separate "jtreg" tests for a set intended to
 * check these for the most central aspects of functionality.) So, most tests use the smallest
 * sensible numbers of threads, collection sizes, etc needed to check basic conformance.</li>
 *
 * <li>The test classes currently do not declare inclusion in any particular package to simplify
 * things for people integrating them in TCK test suites.</li>
 *
 * <li>As a convenience, the {@code main} of this class (JSR166TestCase) runs all JSR166 unit
 * tests.</li>
 *
 * </ul>
 */
abstract class JSR166TestCase extends TestCase {
    private static final boolean useSecurityManager = Boolean.getBoolean("jsr166.useSecurityManager");

    protected static final boolean expensiveTests = Boolean.getBoolean("jsr166.expensiveTests");

    /**
     * If true, report on stdout all "slow" tests, that is, ones that take more than
     * profileThreshold milliseconds to execute.
     */
    private static final boolean profileTests = Boolean.getBoolean("jsr166.profileTests");

    /**
     * The number of milliseconds that tests are permitted for execution without being reported,
     * when profileTests is set.
     */
    private static final long profileThreshold = Long.getLong("jsr166.profileThreshold", 100);

    protected void runTest() throws Throwable {
        if (profileTests)
            runTestProfiled();
        else
            super.runTest();
    }

    protected void runTestProfiled() throws Throwable {
        long t0 = System.nanoTime();
        try {
            super.runTest();
        } finally {
            long elapsedMillis = (System.nanoTime() - t0) / (1000L * 1000L);
            if (elapsedMillis >= profileThreshold)
                System.out.printf("%n%s: %d%n", toString(), elapsedMillis);
        }
    }

    // /**
    // * Runs all JSR166 unit tests using junit.textui.TestRunner
    // */
    // public static void main(String[] args) {
    // if (useSecurityManager) {
    // System.err.println("Setting a permissive security manager");
    // Policy.setPolicy(permissivePolicy());
    // System.setSecurityManager(new SecurityManager());
    // }
    // int iters = (args.length == 0) ? 1 : Integer.parseInt(args[0]);

    // Test s = suite();
    // for (int i = 0; i < iters; ++i) {
    // junit.textui.TestRunner.run(s);
    // System.gc();
    // System.runFinalization();
    // }
    // System.exit(0);
    // }

    // public static TestSuite newTestSuite(Object... suiteOrClasses) {
    // TestSuite suite = new TestSuite();
    // for (Object suiteOrClass : suiteOrClasses) {
    // if (suiteOrClass instanceof TestSuite)
    // suite.addTest((TestSuite) suiteOrClass);
    // else if (suiteOrClass instanceof Class)
    // suite.addTest(new TestSuite((Class<?>) suiteOrClass));
    // else
    // throw new ClassCastException("not a test suite or class");
    // }
    // return suite;
    // }

    // /**
    // * Collects all JSR166 unit tests as one suite.
    // */
    // public static Test suite() {
    // return newTestSuite(
    // ForkJoinPoolTest.suite(),
    // ForkJoinTaskTest.suite(),
    // RecursiveActionTest.suite(),
    // RecursiveTaskTest.suite(),
    // LinkedTransferQueueTest.suite(),
    // PhaserTest.suite(),
    // ThreadLocalRandomTest.suite(),
    // AbstractExecutorServiceTest.suite(),
    // AbstractQueueTest.suite(),
    // AbstractQueuedSynchronizerTest.suite(),
    // AbstractQueuedLongSynchronizerTest.suite(),
    // ArrayBlockingQueueTest.suite(),
    // ArrayDequeTest.suite(),
    // AtomicBooleanTest.suite(),
    // AtomicIntegerArrayTest.suite(),
    // AtomicIntegerFieldUpdaterTest.suite(),
    // AtomicIntegerTest.suite(),
    // AtomicLongArrayTest.suite(),
    // AtomicLongFieldUpdaterTest.suite(),
    // AtomicLongTest.suite(),
    // AtomicMarkableReferenceTest.suite(),
    // AtomicReferenceArrayTest.suite(),
    // AtomicReferenceFieldUpdaterTest.suite(),
    // AtomicReferenceTest.suite(),
    // AtomicStampedReferenceTest.suite(),
    // ConcurrentHashMapTest.suite(),
    // ConcurrentLinkedDequeTest.suite(),
    // ConcurrentLinkedQueueTest.suite(),
    // ConcurrentSkipListMapTest.suite(),
    // ConcurrentSkipListSubMapTest.suite(),
    // ConcurrentSkipListSetTest.suite(),
    // ConcurrentSkipListSubSetTest.suite(),
    // CopyOnWriteArrayListTest.suite(),
    // CopyOnWriteArraySetTest.suite(),
    // CountDownLatchTest.suite(),
    // CyclicBarrierTest.suite(),
    // DelayQueueTest.suite(),
    // EntryTest.suite(),
    // ExchangerTest.suite(),
    // ExecutorsTest.suite(),
    // ExecutorCompletionServiceTest.suite(),
    // FutureTaskTest.suite(),
    // LinkedBlockingDequeTest.suite(),
    // LinkedBlockingQueueTest.suite(),
    // LinkedListTest.suite(),
    // LockSupportTest.suite(),
    // PriorityBlockingQueueTest.suite(),
    // PriorityQueueTest.suite(),
    // ReentrantLockTest.suite(),
    // ReentrantReadWriteLockTest.suite(),
    // ScheduledExecutorTest.suite(),
    // ScheduledExecutorSubclassTest.suite(),
    // SemaphoreTest.suite(),
    // SynchronousQueueTest.suite(),
    // SystemTest.suite(),
    // ThreadLocalTest.suite(),
    // ThreadPoolExecutorTest.suite(),
    // ThreadPoolExecutorSubclassTest.suite(),
    // ThreadTest.suite(),
    // TimeUnitTest.suite(),
    // TreeMapTest.suite(),
    // TreeSetTest.suite(),
    // TreeSubMapTest.suite(),
    // TreeSubSetTest.suite());
    // }

    public static long SHORT_DELAY_MS;
    public static long SMALL_DELAY_MS;
    public static long MEDIUM_DELAY_MS;
    public static long LONG_DELAY_MS;

    /**
     * Returns the shortest timed delay. This could be reimplemented to use for example a Property.
     */
    protected long getShortDelay() {
        return 50;
    }

    /**
     * Sets delays as multiples of SHORT_DELAY.
     */
    protected void setDelays() {
        SHORT_DELAY_MS = getShortDelay();
        SMALL_DELAY_MS = SHORT_DELAY_MS * 5;
        MEDIUM_DELAY_MS = SHORT_DELAY_MS * 10;
        LONG_DELAY_MS = SHORT_DELAY_MS * 200;
    }

    /**
     * Returns a timeout in milliseconds to be used in tests that verify that operations block or
     * time out.
     */
    long timeoutMillis() {
        return SHORT_DELAY_MS / 4;
    }

    /**
     * Returns a new Date instance representing a time delayMillis milliseconds in the future.
     */
    Date delayedDate(long delayMillis) {
        return new Date(System.currentTimeMillis() + delayMillis);
    }

    /**
     * The first exception encountered if any threadAssertXXX method fails.
     */
    private final AtomicReference<Throwable> threadFailure = new AtomicReference<Throwable>(null);

    /**
     * Records an exception so that it can be rethrown later in the test harness thread, triggering
     * a test case failure. Only the first failure is recorded; subsequent calls to this method from
     * within the same test have no effect.
     */
    public void threadRecordFailure(Throwable t) {
        threadFailure.compareAndSet(null, t);
    }

    public void setUp() {
        setDelays();
    }

    /**
     * Extra checks that get done for all test cases.
     *
     * Triggers test case failure if any thread assertions have failed, by rethrowing, in the test
     * harness thread, any exception recorded earlier by threadRecordFailure.
     *
     * Triggers test case failure if interrupt status is set in the main thread.
     */
    public void tearDown() throws Exception {
        Throwable t = threadFailure.getAndSet(null);
        if (t != null) {
            if (t instanceof Error)
                throw (Error) t;
            else if (t instanceof RuntimeException)
                throw (RuntimeException) t;
            else if (t instanceof Exception)
                throw (Exception) t;
            else {
                AssertionFailedError afe = new AssertionFailedError(t.toString());
                afe.initCause(t);
                throw afe;
            }
        }

        if (Thread.interrupted())
            throw new AssertionFailedError("interrupt status set in main thread");
    }

    /**
     * Just like fail(reason), but additionally recording (using threadRecordFailure) any
     * AssertionFailedError thrown, so that the current testcase will fail.
     */
    public void threadFail(String reason) {
        try {
            fail(reason);
        } catch (AssertionFailedError t) {
            threadRecordFailure(t);
            fail(reason);
        }
    }

    /**
     * Just like assertTrue(b), but additionally recording (using threadRecordFailure) any
     * AssertionFailedError thrown, so that the current testcase will fail.
     */
    public void threadAssertTrue(boolean b) {
        try {
            assertTrue(b);
        } catch (AssertionFailedError t) {
            threadRecordFailure(t);
            throw t;
        }
    }

    /**
     * Just like assertFalse(b), but additionally recording (using threadRecordFailure) any
     * AssertionFailedError thrown, so that the current testcase will fail.
     */
    public void threadAssertFalse(boolean b) {
        try {
            assertFalse(b);
        } catch (AssertionFailedError t) {
            threadRecordFailure(t);
            throw t;
        }
    }

    /**
     * Just like assertNull(x), but additionally recording (using threadRecordFailure) any
     * AssertionFailedError thrown, so that the current testcase will fail.
     */
    public void threadAssertNull(Object x) {
        try {
            assertNull(x);
        } catch (AssertionFailedError t) {
            threadRecordFailure(t);
            throw t;
        }
    }

    /**
     * Just like assertEquals(x, y), but additionally recording (using threadRecordFailure) any
     * AssertionFailedError thrown, so that the current testcase will fail.
     */
    public void threadAssertEquals(long x, long y) {
        try {
            assertEquals(x, y);
        } catch (AssertionFailedError t) {
            threadRecordFailure(t);
            throw t;
        }
    }

    /**
     * Just like assertEquals(x, y), but additionally recording (using threadRecordFailure) any
     * AssertionFailedError thrown, so that the current testcase will fail.
     */
    public void threadAssertEquals(Object x, Object y) {
        try {
            assertEquals(x, y);
        } catch (AssertionFailedError t) {
            threadRecordFailure(t);
            throw t;
        } catch (Throwable t) {
            threadUnexpectedException(t);
        }
    }

    /**
     * Just like assertSame(x, y), but additionally recording (using threadRecordFailure) any
     * AssertionFailedError thrown, so that the current testcase will fail.
     */
    public void threadAssertSame(Object x, Object y) {
        try {
            assertSame(x, y);
        } catch (AssertionFailedError t) {
            threadRecordFailure(t);
            throw t;
        }
    }

    /**
     * Calls threadFail with message "should throw exception".
     */
    public void threadShouldThrow() {
        threadFail("should throw exception");
    }

    /**
     * Calls threadFail with message "should throw" + exceptionName.
     */
    public void threadShouldThrow(String exceptionName) {
        threadFail("should throw " + exceptionName);
    }

    /**
     * Records the given exception using {@link #threadRecordFailure}, then rethrows the exception,
     * wrapping it in an AssertionFailedError if necessary.
     */
    public void threadUnexpectedException(Throwable t) {
        threadRecordFailure(t);
        t.printStackTrace();
        if (t instanceof RuntimeException)
            throw (RuntimeException) t;
        else if (t instanceof Error)
            throw (Error) t;
        else {
            AssertionFailedError afe = new AssertionFailedError("unexpected exception: " + t);
            afe.initCause(t);
            throw afe;
        }
    }

    /**
     * Delays, via Thread.sleep, for the given millisecond delay, but if the sleep is shorter than
     * specified, may re-sleep or yield until time elapses.
     */
    static void delay(long millis) throws InterruptedException {
        long startTime = System.nanoTime();
        long ns = millis * 1000 * 1000;
        for (;;) {
            if (millis > 0L)
                Thread.sleep(millis);
            else // too short to sleep
                Thread.yield();
            long d = ns - (System.nanoTime() - startTime);
            if (d > 0L)
                millis = d / (1000 * 1000);
            else
                break;
        }
    }

    /**
     * Waits out termination of a thread pool or fails doing so.
     */
    void joinPool(ExecutorService exec) {
        try {
            exec.shutdown();
            assertTrue("ExecutorService did not terminate in a timely manner",
                    exec.awaitTermination(2 * LONG_DELAY_MS, MILLISECONDS));
        } catch (SecurityException ok) {
            // Allowed in case test doesn't have privs
        } catch (InterruptedException ie) {
            fail("Unexpected InterruptedException");
        }
    }

    /**
     * Checks that thread does not terminate within the default millisecond delay of
     * {@code timeoutMillis()}.
     */
    void assertThreadStaysAlive(Thread thread) {
        assertThreadStaysAlive(thread, timeoutMillis());
    }

    /**
     * Checks that thread does not terminate within the given millisecond delay.
     */
    void assertThreadStaysAlive(Thread thread, long millis) {
        try {
            // No need to optimize the failing case via Thread.join.
            delay(millis);
            assertTrue(thread.isAlive());
        } catch (InterruptedException ie) {
            fail("Unexpected InterruptedException");
        }
    }

    /**
     * Checks that the threads do not terminate within the default millisecond delay of
     * {@code timeoutMillis()}.
     */
    void assertThreadsStayAlive(Thread... threads) {
        assertThreadsStayAlive(timeoutMillis(), threads);
    }

    /**
     * Checks that the threads do not terminate within the given millisecond delay.
     */
    void assertThreadsStayAlive(long millis, Thread... threads) {
        try {
            // No need to optimize the failing case via Thread.join.
            delay(millis);
            for (Thread thread : threads)
                assertTrue(thread.isAlive());
        } catch (InterruptedException ie) {
            fail("Unexpected InterruptedException");
        }
    }

    /**
     * Checks that future.get times out, with the default timeout of {@code timeoutMillis()}.
     */
    void assertFutureTimesOut(Future future) {
        assertFutureTimesOut(future, timeoutMillis());
    }

    /**
     * Checks that future.get times out, with the given millisecond timeout.
     */
    void assertFutureTimesOut(Future future, long timeoutMillis) {
        long startTime = System.nanoTime();
        try {
            future.get(timeoutMillis, MILLISECONDS);
            shouldThrow();
        } catch (TimeoutException success) {
        } catch (Exception e) {
            threadUnexpectedException(e);
        } finally {
            future.cancel(true);
        }
        assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
    }

    /**
     * Fails with message "should throw exception".
     */
    public void shouldThrow() {
        fail("Should throw exception");
    }

    /**
     * Fails with message "should throw " + exceptionName.
     */
    public void shouldThrow(String exceptionName) {
        fail("Should throw " + exceptionName);
    }

    /**
     * The number of elements to place in collections, arrays, etc.
     */
    public static final int SIZE = 20;

    // Some convenient Integer constants

    public static final Integer zero = new Integer(0);
    public static final Integer one = new Integer(1);
    public static final Integer two = new Integer(2);
    public static final Integer three = new Integer(3);
    public static final Integer four = new Integer(4);
    public static final Integer five = new Integer(5);
    public static final Integer six = new Integer(6);
    public static final Integer seven = new Integer(7);
    public static final Integer eight = new Integer(8);
    public static final Integer nine = new Integer(9);
    public static final Integer m1 = new Integer(-1);
    public static final Integer m2 = new Integer(-2);
    public static final Integer m3 = new Integer(-3);
    public static final Integer m4 = new Integer(-4);
    public static final Integer m5 = new Integer(-5);
    public static final Integer m6 = new Integer(-6);
    public static final Integer m10 = new Integer(-10);

    /**
     * Runs Runnable r with a security policy that permits precisely the specified permissions. If
     * there is no current security manager, the runnable is run twice, both with and without a
     * security manager. We require that any security manager permit getPolicy/setPolicy.
     */
    public void runWithPermissions(Runnable r, Permission... permissions) {
        SecurityManager sm = System.getSecurityManager();
        if (sm == null) {
            r.run();
            Policy savedPolicy = Policy.getPolicy();
            try {
                Policy.setPolicy(permissivePolicy());
                System.setSecurityManager(new SecurityManager());
                runWithPermissions(r, permissions);
            } finally {
                System.setSecurityManager(null);
                Policy.setPolicy(savedPolicy);
            }
        } else {
            Policy savedPolicy = Policy.getPolicy();
            AdjustablePolicy policy = new AdjustablePolicy(permissions);
            Policy.setPolicy(policy);

            try {
                r.run();
            } finally {
                policy.addPermission(new SecurityPermission("setPolicy"));
                Policy.setPolicy(savedPolicy);
            }
        }
    }

    /**
     * Runs a runnable without any permissions.
     */
    public void runWithoutPermissions(Runnable r) {
        runWithPermissions(r);
    }

    /**
     * A security policy where new permissions can be dynamically added or all cleared.
     */
    public static class AdjustablePolicy extends java.security.Policy {
        Permissions perms = new Permissions();

        AdjustablePolicy(Permission... permissions) {
            for (Permission permission : permissions)
                perms.add(permission);
        }

        void addPermission(Permission perm) {
            perms.add(perm);
        }

        void clearPermissions() {
            perms = new Permissions();
        }

        public PermissionCollection getPermissions(CodeSource cs) {
            return perms;
        }

        public PermissionCollection getPermissions(ProtectionDomain pd) {
            return perms;
        }

        public boolean implies(ProtectionDomain pd, Permission p) {
            return perms.implies(p);
        }

        public void refresh() {}
    }

    /**
     * Returns a policy containing all the permissions we ever need.
     */
    public static Policy permissivePolicy() {
        return new AdjustablePolicy
        // Permissions j.u.c. needs directly
        (new RuntimePermission("modifyThread"), new RuntimePermission("getClassLoader"),
                new RuntimePermission("setContextClassLoader"),
                // Permissions needed to change permissions!
                new SecurityPermission("getPolicy"), new SecurityPermission("setPolicy"),
                new RuntimePermission("setSecurityManager"),
                // Permissions needed by the junit test harness
                new RuntimePermission("accessDeclaredMembers"), new PropertyPermission("*", "read"),
                new java.io.FilePermission("<<ALL FILES>>", "read"));
    }

    /**
     * Sleeps until the given time has elapsed. Throws AssertionFailedError if interrupted.
     */
    void sleep(long millis) {
        try {
            delay(millis);
        } catch (InterruptedException ie) {
            AssertionFailedError afe = new AssertionFailedError("Unexpected InterruptedException");
            afe.initCause(ie);
            throw afe;
        }
    }

    /**
     * Spin-waits up to the specified number of milliseconds for the given thread to enter a wait
     * state: BLOCKED, WAITING, or TIMED_WAITING.
     */
    void waitForThreadToEnterWaitState(Thread thread, long timeoutMillis) {
        long startTime = System.nanoTime();
        for (;;) {
            Thread.State s = thread.getState();
            if (s == Thread.State.BLOCKED || s == Thread.State.WAITING || s == Thread.State.TIMED_WAITING)
                return;
            else if (s == Thread.State.TERMINATED)
                fail("Unexpected thread termination");
            else if (millisElapsedSince(startTime) > timeoutMillis) {
                threadAssertTrue(thread.isAlive());
                return;
            }
            Thread.yield();
        }
    }

    /**
     * Waits up to LONG_DELAY_MS for the given thread to enter a wait state: BLOCKED, WAITING, or
     * TIMED_WAITING.
     */
    void waitForThreadToEnterWaitState(Thread thread) {
        waitForThreadToEnterWaitState(thread, LONG_DELAY_MS);
    }

    /**
     * Returns the number of milliseconds since time given by startNanoTime, which must have been
     * previously returned from a call to {@link System.nanoTime()}.
     */
    long millisElapsedSince(long startNanoTime) {
        return NANOSECONDS.toMillis(System.nanoTime() - startNanoTime);
    }

    /**
     * Returns a new started daemon Thread running the given runnable.
     */
    Thread newStartedThread(Runnable runnable) {
        Thread t = new Thread(runnable);
        t.setDaemon(true);
        t.start();
        return t;
    }

    /**
     * Waits for the specified time (in milliseconds) for the thread to terminate (using
     * {@link Thread#join(long)}), else interrupts the thread (in the hope that it may terminate
     * later) and fails.
     */
    void awaitTermination(Thread t, long timeoutMillis) {
        try {
            t.join(timeoutMillis);
        } catch (InterruptedException ie) {
            threadUnexpectedException(ie);
        } finally {
            if (t.getState() != Thread.State.TERMINATED) {
                t.interrupt();
                fail("Test timed out");
            }
        }
    }

    /**
     * Waits for LONG_DELAY_MS milliseconds for the thread to terminate (using
     * {@link Thread#join(long)}), else interrupts the thread (in the hope that it may terminate
     * later) and fails.
     */
    void awaitTermination(Thread t) {
        awaitTermination(t, LONG_DELAY_MS);
    }

    // Some convenient Runnable classes

    public abstract class CheckedRunnable implements Runnable {
        protected abstract void realRun() throws Throwable;

        public final void run() {
            try {
                realRun();
            } catch (Throwable t) {
                threadUnexpectedException(t);
            }
        }
    }

    public abstract class RunnableShouldThrow implements Runnable {
        protected abstract void realRun() throws Throwable;

        final Class<?> exceptionClass;

        <T extends Throwable> RunnableShouldThrow(Class<T> exceptionClass) {
            this.exceptionClass = exceptionClass;
        }

        public final void run() {
            try {
                realRun();
                threadShouldThrow(exceptionClass.getSimpleName());
            } catch (Throwable t) {
                if (!exceptionClass.isInstance(t))
                    threadUnexpectedException(t);
            }
        }
    }

    public abstract class ThreadShouldThrow extends Thread {
        protected abstract void realRun() throws Throwable;

        final Class<?> exceptionClass;

        <T extends Throwable> ThreadShouldThrow(Class<T> exceptionClass) {
            this.exceptionClass = exceptionClass;
        }

        public final void run() {
            try {
                realRun();
                threadShouldThrow(exceptionClass.getSimpleName());
            } catch (Throwable t) {
                if (!exceptionClass.isInstance(t))
                    threadUnexpectedException(t);
            }
        }
    }

    public abstract class CheckedInterruptedRunnable implements Runnable {
        protected abstract void realRun() throws Throwable;

        public final void run() {
            try {
                realRun();
                threadShouldThrow("InterruptedException");
            } catch (InterruptedException success) {
                threadAssertFalse(Thread.interrupted());
            } catch (Throwable t) {
                threadUnexpectedException(t);
            }
        }
    }

    public abstract class CheckedCallable<T> implements Callable<T> {
        protected abstract T realCall() throws Throwable;

        public final T call() {
            try {
                return realCall();
            } catch (Throwable t) {
                threadUnexpectedException(t);
                return null;
            }
        }
    }

    public abstract class CheckedInterruptedCallable<T> implements Callable<T> {
        protected abstract T realCall() throws Throwable;

        public final T call() {
            try {
                T result = realCall();
                threadShouldThrow("InterruptedException");
                return result;
            } catch (InterruptedException success) {
                threadAssertFalse(Thread.interrupted());
            } catch (Throwable t) {
                threadUnexpectedException(t);
            }
            return null;
        }
    }

    public static class NoOpRunnable implements Runnable {
        public void run() {}
    }

    public static class NoOpCallable implements Callable {
        public Object call() {
            return Boolean.TRUE;
        }
    }

    public static final String TEST_STRING = "a test string";

    public static class StringTask implements Callable<String> {
        public String call() {
            return TEST_STRING;
        }
    }

    public Callable<String> latchAwaitingStringTask(final CountDownLatch latch) {
        return new CheckedCallable<String>() {
            protected String realCall() {
                try {
                    latch.await();
                } catch (InterruptedException quittingTime) {
                }
                return TEST_STRING;
            }
        };
    }

    public Runnable awaiter(final CountDownLatch latch) {
        return new CheckedRunnable() {
            public void realRun() throws InterruptedException {
                await(latch);
            }
        };
    }

    public void await(CountDownLatch latch) {
        try {
            assertTrue(latch.await(LONG_DELAY_MS, MILLISECONDS));
        } catch (Throwable t) {
            threadUnexpectedException(t);
        }
    }

    public void await(Semaphore semaphore) {
        try {
            assertTrue(semaphore.tryAcquire(LONG_DELAY_MS, MILLISECONDS));
        } catch (Throwable t) {
            threadUnexpectedException(t);
        }
    }

    // /**
    // * Spin-waits up to LONG_DELAY_MS until flag becomes true.
    // */
    // public void await(AtomicBoolean flag) {
    // await(flag, LONG_DELAY_MS);
    // }

    // /**
    // * Spin-waits up to the specified timeout until flag becomes true.
    // */
    // public void await(AtomicBoolean flag, long timeoutMillis) {
    // long startTime = System.nanoTime();
    // while (!flag.get()) {
    // if (millisElapsedSince(startTime) > timeoutMillis)
    // throw new AssertionFailedError("timed out");
    // Thread.yield();
    // }
    // }

    public static class NPETask implements Callable<String> {
        public String call() {
            throw new NullPointerException();
        }
    }

    public static class CallableOne implements Callable<Integer> {
        public Integer call() {
            return one;
        }
    }

    public class ShortRunnable extends CheckedRunnable {
        protected void realRun() throws Throwable {
            delay(SHORT_DELAY_MS);
        }
    }

    public class ShortInterruptedRunnable extends CheckedInterruptedRunnable {
        protected void realRun() throws InterruptedException {
            delay(SHORT_DELAY_MS);
        }
    }

    public class SmallRunnable extends CheckedRunnable {
        protected void realRun() throws Throwable {
            delay(SMALL_DELAY_MS);
        }
    }

    public class SmallPossiblyInterruptedRunnable extends CheckedRunnable {
        protected void realRun() {
            try {
                delay(SMALL_DELAY_MS);
            } catch (InterruptedException ok) {
            }
        }
    }

    public class SmallCallable extends CheckedCallable {
        protected Object realCall() throws InterruptedException {
            delay(SMALL_DELAY_MS);
            return Boolean.TRUE;
        }
    }

    public class MediumRunnable extends CheckedRunnable {
        protected void realRun() throws Throwable {
            delay(MEDIUM_DELAY_MS);
        }
    }

    public class MediumInterruptedRunnable extends CheckedInterruptedRunnable {
        protected void realRun() throws InterruptedException {
            delay(MEDIUM_DELAY_MS);
        }
    }

    public Runnable possiblyInterruptedRunnable(final long timeoutMillis) {
        return new CheckedRunnable() {
            protected void realRun() {
                try {
                    delay(timeoutMillis);
                } catch (InterruptedException ok) {
                }
            }
        };
    }

    public class MediumPossiblyInterruptedRunnable extends CheckedRunnable {
        protected void realRun() {
            try {
                delay(MEDIUM_DELAY_MS);
            } catch (InterruptedException ok) {
            }
        }
    }

    public class LongPossiblyInterruptedRunnable extends CheckedRunnable {
        protected void realRun() {
            try {
                delay(LONG_DELAY_MS);
            } catch (InterruptedException ok) {
            }
        }
    }

    /**
     * For use as ThreadFactory in constructors
     */
    public static class SimpleThreadFactory implements ThreadFactory {
        public Thread newThread(Runnable r) {
            return new Thread(r);
        }
    }

    public interface TrackedRunnable extends Runnable {
        boolean isDone();
    }

    public static TrackedRunnable trackedRunnable(final long timeoutMillis) {
        return new TrackedRunnable() {
            private volatile boolean done = false;

            public boolean isDone() {
                return done;
            }

            public void run() {
                try {
                    delay(timeoutMillis);
                    done = true;
                } catch (InterruptedException ok) {
                }
            }
        };
    }

    public static class TrackedShortRunnable implements Runnable {
        public volatile boolean done = false;

        public void run() {
            try {
                delay(SHORT_DELAY_MS);
                done = true;
            } catch (InterruptedException ok) {
            }
        }
    }

    public static class TrackedSmallRunnable implements Runnable {
        public volatile boolean done = false;

        public void run() {
            try {
                delay(SMALL_DELAY_MS);
                done = true;
            } catch (InterruptedException ok) {
            }
        }
    }

    public static class TrackedMediumRunnable implements Runnable {
        public volatile boolean done = false;

        public void run() {
            try {
                delay(MEDIUM_DELAY_MS);
                done = true;
            } catch (InterruptedException ok) {
            }
        }
    }

    public static class TrackedLongRunnable implements Runnable {
        public volatile boolean done = false;

        public void run() {
            try {
                delay(LONG_DELAY_MS);
                done = true;
            } catch (InterruptedException ok) {
            }
        }
    }

    public static class TrackedNoOpRunnable implements Runnable {
        public volatile boolean done = false;

        public void run() {
            done = true;
        }
    }

    public static class TrackedCallable implements Callable {
        public volatile boolean done = false;

        public Object call() {
            try {
                delay(SMALL_DELAY_MS);
                done = true;
            } catch (InterruptedException ok) {
            }
            return Boolean.TRUE;
        }
    }

    // /**
    // * Analog of CheckedRunnable for RecursiveAction
    // */
    // public abstract class CheckedRecursiveAction extends RecursiveAction {
    // protected abstract void realCompute() throws Throwable;

    // public final void compute() {
    // try {
    // realCompute();
    // } catch (Throwable t) {
    // threadUnexpectedException(t);
    // }
    // }
    // }

    // /**
    // * Analog of CheckedCallable for RecursiveTask
    // */
    // public abstract class CheckedRecursiveTask<T> extends RecursiveTask<T> {
    // protected abstract T realCompute() throws Throwable;

    // public final T compute() {
    // try {
    // return realCompute();
    // } catch (Throwable t) {
    // threadUnexpectedException(t);
    // return null;
    // }
    // }
    // }

    /**
     * For use as RejectedExecutionHandler in constructors
     */
    public static class NoOpREHandler implements RejectedExecutionHandler {
        public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {}
    }

    /**
     * A CyclicBarrier that uses timed await and fails with AssertionFailedErrors instead of
     * throwing checked exceptions.
     */
    public class CheckedBarrier extends CyclicBarrier {
        public CheckedBarrier(int parties) {
            super(parties);
        }

        public int await() {
            try {
                return super.await(2 * LONG_DELAY_MS, MILLISECONDS);
            } catch (TimeoutException e) {
                throw new AssertionFailedError("timed out");
            } catch (Exception e) {
                AssertionFailedError afe = new AssertionFailedError("Unexpected exception: " + e);
                afe.initCause(e);
                throw afe;
            }
        }
    }

    void checkEmpty(BlockingQueue q) {
        try {
            assertTrue(q.isEmpty());
            assertEquals(0, q.size());
            assertNull(q.peek());
            assertNull(q.poll());
            assertNull(q.poll(0, MILLISECONDS));
            assertEquals(q.toString(), "[]");
            assertTrue(Arrays.equals(q.toArray(), new Object[0]));
            assertFalse(q.iterator().hasNext());
            try {
                q.element();
                shouldThrow();
            } catch (NoSuchElementException success) {
            }
            try {
                q.iterator().next();
                shouldThrow();
            } catch (NoSuchElementException success) {
            }
            try {
                q.remove();
                shouldThrow();
            } catch (NoSuchElementException success) {
            }
        } catch (InterruptedException ie) {
            threadUnexpectedException(ie);
        }
    }

    @SuppressWarnings("unchecked")
    <T> T serialClone(T o) {
        try {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(bos);
            oos.writeObject(o);
            oos.flush();
            oos.close();
            ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(bos.toByteArray()));
            T clone = (T) ois.readObject();
            assertSame(o.getClass(), clone.getClass());
            return clone;
        } catch (Throwable t) {
            threadUnexpectedException(t);
            return null;
        }
    }
}
